Now ARS scientists in Beltsville, Md., have shown that two beautyberry compoundscallicarpenal and intermedeolmay effectively repel blacklegged ticks as well.

Blacklegged ticks are the principal carrier of bacteria that in humans cause Lyme disease, an affliction known for its fevers, headaches and bull's-eye rash. Left untreated, this disease can cause severe and chronic illness.

Blacklegged ticks, Ixodes scapularis, are the principal carrier of bacteria that cause Lyme disease in humans. Preliminary studies by ARS scientists in Maryland have shown that compounds from American beautyberry plants may have use as repellents against them. Click the images for more information about them.

The treated strips repelled more than 95 percent of blacklegged tick nymphs.

Callicarpenal did especially well in a separate duration test, repelling all the blacklegged ticks tested for three hours after application, and 53 percent after four hours.

The researchers also tested the natural compounds against nymphs of lone star ticks, which transmit potentially serious human diseases known as ehrlichioses.

The two compounds, as well as DEET, were considerably more potent against blacklegged ticks than against lone star ticks. An experimental repellent developed by ARS and known as SS220 was most effective against the lone star variety.

While the findings are preliminary, the beautyberry compounds' usage history leads Carroll to believe that callicarpenal and intermedeol have potential for human use.